JPH051964B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention provides a resistor that can be formed into a thick film resistor or a similar resistor by firing in a non-oxidizing atmosphere and has high moisture resistance. The present invention relates to a paste-like resistance material that can be used. [Prior art] An unfired ceramic sheet (green sheet) coated with a conductor paste of a base metal such as nickel and a resistor paste containing molybdenum boride, fluoride, and glass is heated in a non-oxidizing atmosphere. A method of firing a multilayer ceramic circuit board having both thick film conductors and thick film resistors is disclosed in commonly assigned Japanese Patent Application No. 1976-197. In this method, no precious metals are used to form the thick film conductors and thick film resistors;
The cost of multilayer ceramic circuit boards can be reduced. [Problems to be Solved by the Invention] However, the thick film resistor formed from the resistive material according to the above application does not have sufficient moisture resistance. For example, when left in an environment with a temperature of 60°C and a relative humidity of 95% for 1000 hours, the rate of change in resistance will be about +5% to +10%. Therefore, an object of the present invention is to provide a resistor material that can be formed into a resistor by firing in a non-oxidizing atmosphere and that can have a resistance change rate within ±2% in a humidity test. There is a particular thing. [Means for Solving the Problems] The resistance material according to the present invention for achieving the above object includes 25 to 75% by weight of tungsten carbide, 10 to 50% by weight of glass, calcium fluoride (CaF ₂ ), 5 to 40% by weight of at least one fluoride selected from strontium fluoride (SrF ₂ ) and barium fluoride (BaF ₂ ), and calcium carbonate (CaCO ₃ ), strontium carbonate (SrCO ₃ ), and barium carbonate (BaCO ₃ ), an organic binder, and a solvent. [Function] By printing a paste-like resistance material having the above composition on a green sheet and baking it in a non-oxidizing atmosphere, a thick film resistor having a resistance change rate within ±2% in a humidity test can be obtained. Therefore, a base metal thick film resistor can be formed simultaneously with the formation of a thick film conductor using a conductor paste of a base metal such as nickel. [Example 1] Next, a resistor material according to an example of the present invention and a method of forming a multilayer ceramic circuit board using the same will be described. First, 78.0 parts by weight of silicon dioxide (SiO ₂ ), 5.5 parts by weight of zinc oxide (ZnO), and zirconium oxide (ZrO ₂ ).
12.0 parts by weight, 3.0 parts by weight of calcium carbonate (CaCO ₃ ), and 1.5 parts by weight of aluminum oxide (Al ₂ O ₃ ) were mixed, melted in an aluminum pot at 1400°C for 30 minutes, and the melt was poured into water. Cooled rapidly. Take out this quenched material and put it in an alumina mortar, about
Grind it to about 50 μm, then put it in a polyethylene pot mill with ethanol and grind it with an alumina pole for 150 hours until the particle size is reduced.
A powdered glass with a size of 10 μm or less was obtained. Next, the above glass, tungsten carbide (one or more of WC, W ₂ C), and fluoride (one or more of CaF ₂ , SrF ₂ , BaF ₂ ) were weighed in the proportions shown in the table. The mixture was placed in a pole mill and stirred. Next, this was heated to 1200℃ in an argon gas atmosphere.
The mixture was heat-treated for 1 hour, and then placed in a polyethylene pot mill with ethanol and ground for 24 hours with an alumina pole to obtain a powder of a mixture of tungsten carbide, glass, and fluoride with a particle size of 10 μm or less. That is, mixed powders of glass, tungsten carbide, and fluoride in various proportions shown in Sample Nos. 1 to 26 in the table were obtained. Next, glass, tungsten carbide, fluoride, and carbonate (one or more of CaCO ₃ , SrCO ₃ , BaCO ₃ )
Carbonate is added to the above-mentioned mixed powder of glass, tungsten carbide, and fluoride and mixed so that the weight ratio of A powder of a mixture of resistance materials according to the present invention was obtained. That is, in sample No. 1, the composition of the resistance material mixture was 10% by weight of glass, 25% by weight of W ₂ C, 5% by weight of CaF ₂ , and 60% by weight of CaCO ₃ , and in the remaining samples Nos. 2 to 26 as well. The composition had the weight percentage shown in the composition column. Next, 100 parts by weight of the powder of the mixture of resistance materials of each sample was added with 10 parts of ethylcellulose as an organic binder.
An organic binder solution, ie, 25 parts by weight of a vehicle, consisting of 90 parts by weight of butyl carbitol as a solvent was added and kneaded in a three-roll mill to obtain a resistor paste with about 800 voids. On the other hand, a green sheet for printing the above resistor paste was produced by the following method. _{Al2O3 powder}
ceramic raw material powder consisting of 50 parts by weight, 20 parts by weight of SiO ₂ powder, 25 parts by weight of SrO powder, 1 part by weight of Li ₂ O powder, and 4 parts by weight of MgO powder, a binder consisting of an aqueous solution of acrylic acid ester polymer, and glycerin. , a carboxylic acid salt, and water are each placed in a pole mill and mixed to make a slip,
After degassing, the thickness is measured using the doctor blade method.
A 200 μm long green sheet was produced. And from this green sheet, 9mm x 9mm and 6mm
Two types of green sheet pieces measuring 9 mm were cut out. Next, as shown in FIG.
A conductive paste prepared by kneading 90 parts by weight of Ni conductor paste in a ratio of 3:1 was printed using a 200 mesh screen and dried at 125°C for 10 minutes to form a Ni conductor as shown in Figure 1. Film 2 was formed. Next, the resistor paste according to the present invention was screen printed in the same manner as the conductor paste and dried to form a resistor film 3 as shown in FIG. Next, on top of the green sheet piece 1, another green sheet piece 4 of the size indicated by the chain line is laminated,
Thermocompression bonding is carried out at 100℃ and 150Kg/cm ² , and then heat treated at 500℃ in an oxidizing atmosphere to scatter and decompose the organic binder and solvent (organic vehicle), and N ₂ (98.5% by volume)
+H ₂ (1.5% by volume) at 1100℃, 2
As shown in FIG. 2, the porcelain layers 1a and 4
A multilayer ceramic circuit board for a hybrid integrated circuit having a thick film conductor 2a and a thick film resistor 3a was completed. The size of the portion of the resistor 3a that does not cover the conductor 2a is 3 mm x 3 mm, and the film thickness is 18 μm. Further, the composition of the resistor 3a substantially matches the inorganic composition of the resistor material before firing. Next, the sheet resistance R ₀ (Ω/□) of this resistor 3a at 25° C. was measured using a digital multimeter. Next, each sample (multilayer ceramic circuit board) was left in an environment with a temperature of 60°C and a relative humidity of 95% for 1000 hours, and then the sheet resistance R ₁ (Ω/□) was measured again using a digital multimeter. The resistance change rate △R of the thick film conductor 2a during the test is (R ₁
−R ₀ /R ₀ )×100%. The above R ₀ and ΔR are shown in the characteristics column of the table. Note that k in the R ₀ value column means ×10 ³ .

【table】

[Example 2]

In order to confirm that the same effects as in Example 1 can be obtained even if the composition of the glass is changed, glass powder was prepared as follows. Silicon dioxide (SiO ₂ )
75.0 parts by weight, 13.0 parts by weight of diboron trioxide (B ₂ O ₃ ), 10.0 parts by weight of calcium carbonate (CaCO ₃ ), and 2.0 parts by weight of aluminum oxide (Al ₂ O ₃ ),
Powdered glass was obtained in the same manner as in Example 1. Next, using this glass, glass 10% by weight,
WC 25% by weight, W ₂ C 25% by weight, CaF ₂ 5% by weight,
SrF ₂ 5% by weight, BaF ₂ 5% by weight, SrCO ₃ 15% by weight,
A mixture of resistive materials consisting of 10% by weight of BaCO ₃ was obtained in the same manner as in Example 1 and used to form a multilayer ceramic circuit board of the same structure in the same manner as in Example 1. When the electrical characteristics were measured in the same manner as above, the sheet resistance value was 1.762kΩ/□,
The resistance change rate ΔR was -0.8%. As is clear from Example 2, there is no significant difference in resistance characteristics even if the composition of the glass is changed. That is, the glass used in the present invention is not necessarily limited to one specified composition. Note that SiO ₂ −ZnO− in Example 1
ZrO ₂ -CaO-Al ₂ O ₃ -based glass, SiO ₂ - of Example 2
All B ₂ O ₃ -CaO-Al ₂ O ₃ type glasses have a working point (temperature at which 1×10 ⁴ noise is obtained) of 900 to 1200°C. The glass according to the present invention is Example 1
900~
Metal oxides (PbO,
Any material may be used as long as it does not contain SnO ₂ , Bi ₂ O ₃ , etc.). [Modifications] The present invention is not limited to the above-described embodiments, and, for example, the following modifications are possible. (a) Even if the firing temperature of a green sheet coated with a resistor paste containing tungsten carbide, glass, fluoride, and carbonate is varied in the range of 1000℃ to 1200℃, the resistance value R ₀ and the resistance change rate △ It has been confirmed that R hardly changes. For example, when using the same composition as sample No. 11 of Example 1 and changing only the firing temperature to 1000°C, 1050°C, 1150°C, and 1200°C, the resistance value R ₀ is 41.54 kΩ/□,
41.62kΩ/□, 41.39kΩ/□, 41.42kΩ/□, and the resistance change rate △R is +1.5%, +1.6%, +
It was 1.4% and +1.3%. Almost similar results were obtained with other compositions. (b) The atmosphere when firing the green sheet may be a neutral atmosphere (inert atmosphere). Also,
The heat treatment temperature in an oxidizing atmosphere for decomposing and scattering organic matter before firing the green sheet may be varied, for example, from 400°C to 600°C. (c) Calcination temperature of a mixture of glass, tungsten carbide, and fluoride in an argon atmosphere, e.g.
It may be changed within the range of 900 to 1200°C. In addition, this firing is performed in an inert atmosphere other than argon gas.
Alternatively, it may be carried out in vacuum, in a neutral atmosphere, or in a reducing atmosphere. (d) The organic binder solution (vehicle) for making the resistor paste may be one in which a resin such as nitrocellulose is dissolved in a high boiling point solvent such as turpentine oil or butyl carbitol acetate. Further, the amount of this organic binder solution is preferably about 15 to 35 parts by weight. [Effects of the Invention] As is clear from the above, the paste-like resistive material of the present invention and the conductive paste of a base metal such as nickel can be co-fired in a non-oxidizing atmosphere, and the resistive material of the present invention does not contain a noble metal. Not yet. Therefore, it is possible to contribute to miniaturization and cost reduction of multilayer ceramic circuit boards or similar electric circuit components. Furthermore, the resistive material of the present invention can provide a resistor with better moisture resistance than the resistive material of the patent application mentioned above.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing patterns of a green sheet, a conductor film, and a resistor film when manufacturing a multilayer ceramic circuit board according to an embodiment of the present invention, and FIG. 2 is a portion corresponding to the - line in FIG. 1. FIG. 3 is a cross-sectional view showing the multilayer ceramic circuit board after firing. 1... Green sheet piece, 2... Conductor film, 3...
...Resistor film, 4... Green sheet piece.

Claims (1)

[Claims] 1. 25-75% by weight of tungsten carbide, 10-50% by weight of glass, 5-40% of at least one fluoride selected from calcium fluoride, strontium fluoride, and barium fluoride.
Weight %, at least one carbonate of calcium carbonate, strontium carbonate, and barium carbonate 10-60
A paste-like resistance material consisting of a powder mixture consisting of % by weight, an organic binder, and a solvent. 2 The tungsten carbide includes monotungsten monocarbide (WC) and ditungsten monocarbide (W ₂ C).
The resistance material according to claim 1, which is at least one of the following. 3. The resistance material according to claim 1 or 2, wherein the glass has a working point in the range of 900 to 1200°C.